The Iraqi defence ministry said it had received delegations led by their respective deputy chiefs of staff, to "strengthen cooperation and coordination in terms of security and intelligence between these countries".
Iran Guards say they killed 10 militants near Iraq border
Russia is fighting militants and extremists in Syria alongside President Bashar al-Assad's forces, while Iran is a key ally of both Baghdad and Damascus.
The four countries had created joint operations rooms to coordinate the fight against Islamic State, now driven out of all urban centres in Iraq and largely confined to desert holdouts in Syria.
In a rare address last month, the extremist group's leader Abu Bakr al-Baghdadi urged his followers to continue their fight.
Dutch former defence minister appointed UN Iraq envoy
According to jihadist expert Hisham al-Hashemi, there are still 2,000 Islamic State fighters - nearly all of them Iraqi - active in four regions of Iraq. Their aim is "to take revenge on those that ousted them", he said.
Despite major setbacks in Iraq and Syria, in July Islamic State managed to carry out a string of coordinated attacks in southern Syria that killed more than 250 people.
COMMENTS (1)
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ